1. Technical Field
The present invention relates in general to an improved data processing system and in particular to an improved method for managing access to a plurality of objects stored within a distributed data processing system. Still more particularly, the present invention relates to an improved method and system for controlling access to objects stored within a distributed data processing system wherein access to those objects may be selectively locked by users within the distributed data processing system.
2. Description of the Related Art
Data processing systems are becoming increasingly widespread in their application and use within the work environment. As the technology of these systems increases, the number of users and the complexity of applications which may be utilized within such systems has also increased.
One area in which distributed data processing systems have promoted efficiency in the work place is the ability of such systems to permit multiple users to access a single document, application or resource. Such systems typically operate utilizing one of two techniques. In a collaborative computer system, a real-time computer based environment is provided for coordinating individual efforts toward completion of a task. The task or the subject of a group's attention may be a document, a production schedule, a computer program, a product design, or a still or full motion video image or other multimedia selected tasks, solution of which is represented by the organized expression of information. The construction of that expression is presumed to be aided by the efforts of more than one person and particularly by the simultaneous efforts of more than one person.
In many collaborative systems concurrent access to objects within the system is permitted by each of a plurality of users. This issue raises a number of subsidiary issues. For example, user access may be limited to the ability to read an object, but more commonly includes some rights to manipulate or change the object. Such access is typically provided through a multiuser interface which generally includes a video monitor under the control of the user's local workstation, through which views of the shared data object are displayed. In a strict collaborative system, each user displays the exact same subject matter from the same viewpoint and each user is given apparent immediate rights to manipulate the shared object. Such systems often give rise to conflicts or collisions within the system based upon user actions, such as simultaneous attempts to change the same word in a word processing document.
In a more simplified system, typically referred to as a Computer Supported Cooperative Work (CSCW) environment, multiple users may attempt to access the same document at the same time and selected users may be permitted to "lock" the document for some period of time, permitting that user to have exclusive access to the document. During the period of time when a first user has a document restricted by a "lock" other users wishing to use that document will be told that the resource is "locked" and thus their attempt at accessing the document will be thwarted. The efficiency of a user within a CSCW system is thus diminished by a requirement that the user periodically check back to determine whether or not the document or object to which access is desired is available.
It should therefore be apparent that a need exists for a system which may be utilized to identify changes in the lock status of an object within a Computer Supported Cooperative Work (CSCW) system, and to efficiently inform those users interested in access to an object that the lock status of an object has changed.